infrastructure, the compiler isn't smart enough to replace const static
int with the constant, and allocates space for each set of them,
bloating the executable something fierce. Oops.
So now, we #define ENABLE_XXX to 0 or 1 for each CONFIG_XXX (which
is still there so the 1000+ #ifdef/#ifndef tests don't have to be
replaced wholesale). Changed the test instance in networking/ifconfig.c
to use this.